Bistable magnetic driver and manufacturing method thereof

Abstract

The invention belongs to the technical field of magnetic drivers, and particularly discloses a bistable magnetic driver and a manufacturing method thereof. According to the application, the magnetic soft body layer is additionally arranged on the bistable composite material layer, the magnetic soft body layer comprises the magnetic particles which are uniformly laid, the magnetic particles are magnetized before being cured, the magnetization direction is the axial direction or the circumferential direction of the surface of the bistable composite material layer, and the direction of a uniform magnetic field for driving is inward or outward along the surface of the cylindrical shell, so that the magnetic soft body layer can be used for driving the bistable composite material layer. Deviation exists between the uniform magnetic field and the magnetization direction of the magnetic particles, the uniform magnetic field can generate magnetic moment to drive the magnetic soft body layer, and the problems that in a traditional gradient magnetic field force driving mode, magnetic field gradient attenuation is large, and driving is difficult when the separation distance is long are solved. The magnetic soft body layer is prepared through injection molding, overall magnetizing and cutting as required, direct standing curing is performed during preparation, then rapid magnetizing is performed, and the problems that the requirement for the preparation environment is strict, and the magnetization direction is difficult to control and change are solved.

Description

Technical Field

[0001] The present application belongs to the technical field of magnetic actuators, and more specifically, to a bistable magnetic actuator and a method for manufacturing the same. Background Art

[0002] Bistable composite materials have the advantages of light weight, excellent mechanical properties and bistable configuration, and have broad application prospects in high-tech fields such as aerospace, machinery, and electronics. They generally use hydraulic, pneumatic or direct loading methods for contact drive and control, which is less flexible; the magnetic bistable composite materials developed in recent years have shown unique application potential and advantages because they can achieve non-contact drive under the action of a magnetic field.

[0003] Patent CN111416546A discloses a magnetic field driven bistable structure and its manufacturing method, the structure uses orthogonally laid composite laminates, and the magnetosensitive deformation driver is bonded to both ends of the laminate, so that the material structure can be switched between two stable states under the action of the magnetic field. Patent CN114227741A discloses a multi-stable manipulator driven by magnetorheological elastomer, the manipulator includes two deformation units, and the magnetorheological elastomer driver is bonded to one end of the deformation unit, which can realize the switching between three different stable states under the drive of the magnetic field.

[0004] However, the existing magnetically driven bistable structure has the following shortcomings: 1) When the composite laminate is laid in an orthogonal manner, its deformation is small, and the bending directions of the two stable states are opposite, which makes it difficult to design in application scenarios; 2) When the composite laminate is laid in an antisymmetric manner, the deformation amplitude is large due to the material structure itself, which further requires a large driving force for deformation, and it is difficult to drive the bonded magnetorheological elastomer with a single magnetization direction; 3) Most of the existing driving methods use gradient magnetic field forces to produce deformation, which has problems such as severe magnetic field gradient attenuation, single deformation mode, and strict requirements on magnetic field direction. The production of the existing magnetically driven bistable structure has the following shortcomings: the magnetically sensitive deformation driver or magnetorheological elastomer is made of silicone rubber and magnetic particles after being mixed evenly and then left to stand for 2 hours in a uniform magnetic field of 1.5T for curing. The external magnetic field lasts for a long time during preparation, which has strict requirements on the preparation environment and is difficult to control and change the magnetization direction. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of this application is to provide a bistable magnetic actuator and a method for manufacturing the same, aiming to solve the problems of severe magnetic field gradient attenuation and strict requirements on magnetic field direction when the existing bistable composite material structure is deformed by gradient magnetic field drive.

[0006] To achieve the above objectives, in a first aspect, the present application provides a bistable magnetic actuator, comprising: a bistable composite material layer and a magnetic soft layer covering the upper surface and / or lower surface of the bistable composite material layer;

[0007] The bistable composite material layer is a laminated cylindrical shell structure;

[0008] The magnetic soft layer is a rectangular parallelepiped structure, and adaptively presents a cylindrical shell shape as the bistable composite material layer solidifies;

[0009] The magnetic soft layer comprises uniformly laid magnetic particles, which are magnetized before solidification, and the magnetization direction is axial or circumferential on the surface of the bistable composite material layer.

[0010] Preferably, the magnetic soft layer is multi-directionally magnetized so that its deformation trend is consistent with that of the surface of the bistable composite material layer.

[0011] Preferably, the magnetic soft layer is divided into four regions along a diagonal line, the first region and the third region are identical and arranged opposite to each other, and the second region and the fourth region are identical and arranged opposite to each other.

[0012] Preferably, the magnetization direction of the first region and the third region is along the axial direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell; the magnetization direction of the second region and the fourth region is along the circumferential direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell, and the bistable magnetic drive is in a first stable state.

[0013] Preferably, the magnetization direction of the second region and the fourth region is along the axial direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell; the magnetization direction of the first region and the third region is along the circumferential direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell, and the bistable magnetic drive is in a second stable state.

[0014] Preferably, the thickness of the magnetic soft layer is 0.5 mm-1 mm.

[0015] Preferably, the unidirectional fiber reinforced composite material in the bistable composite material layer is laid in an anti-symmetrical manner.

[0016] Preferably, the bistable magnetic actuator is in the shape of a cylindrical shell in both stable states, and the bending directions in the two stable states are the same.

[0017] Preferably, the bistable magnetic drive is applied to a flexible gripper or a multistable robot.

[0018] To achieve the above objectives, in a second aspect, the present application provides a method for manufacturing a bistable magnetic actuator, comprising:

[0019] S1. Mixing the uncured soft base material liquid with the magnetic particles and stirring them evenly to obtain a magnetic mixture fluid;

[0020] S2. injecting the magnetic mixture fluid into a rectangular parallelepiped mold, performing injection molding and curing, and obtaining an unmagnetized rectangular parallelepiped magnetic soft structure after standing and curing;

[0021] S3. placing the unmagnetized rectangular magnetic soft structure in a uniform pulse magnetic field for magnetization to obtain a rectangular magnetic soft structure with a specific magnetization direction;

[0022] S4. The uncured composite single-layer plate is cut according to a preset laying angle, and then laid according to a preset laying method to obtain an uncured anti-symmetrically laid composite laminate;

[0023] S5. Cut the rectangular magnetic soft structure with a specific magnetization direction obtained in S3 according to a preset shape and magnetization direction, and use the same uncured soft base material liquid as in S1 as an adhesive to bond all the magnetic soft structures with a preset shape and magnetization direction to the upper surface and / or lower surface of the uncured anti-symmetrically laid composite material laminate obtained in S4 in a preset manner to obtain an uncured magnetic actuator;

[0024] S6. Placing the uncured magnetic actuator in a cylindrical mold for heating and curing to obtain a magnetic actuator with bistable characteristics.

[0025] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art:

[0026] (1) The present application provides a bistable magnetic actuator, which is achieved by adding a magnetic soft layer on a bistable composite material layer, wherein the magnetic soft layer includes uniformly laid magnetic particles, and the magnetic particles are magnetized before solidification, and the magnetization direction is axial or circumferential on the surface of the bistable composite material layer, while the direction of the uniform magnetic field used for driving is inward or outward along the surface of the cylindrical shell. Therefore, there is a deviation between the uniform magnetic field and the magnetization direction of the magnetic particles. The uniform magnetic field can generate a magnetic torque to drive the magnetic soft structure, thereby avoiding the problem of large magnetic field gradient attenuation and difficulty in driving when the separation distance is long under the traditional gradient magnetic field force driving method.

[0027] (2) The present application provides a method for manufacturing a bistable magnetic actuator, wherein a magnetic soft layer is prepared by injection molding, overall magnetization, and cutting as needed. During the preparation, the magnetic soft layer is directly left to solidify and then rapidly magnetized, thereby avoiding the problems of the existing preparation method, such as long duration of the external magnetic field, strict requirements on the preparation environment, and difficulty in controlling and changing the magnetization direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of a bistable magnetic driver provided in an embodiment of the present application.

[0029] Figure 2 Schematic diagram of two stable states of a bistable composite laminated cylindrical shell provided in an embodiment of the present application, wherein (a) corresponds to a first stable state and (b) corresponds to a second stable state.

[0030] Figure 3 It is a schematic diagram of the torque direction required for the stable state conversion of the bistable composite laminated cylindrical shell provided in an embodiment of the present application, wherein (a) corresponds to the conversion from the first stable state to the second stable state, and (b) corresponds to the conversion from the second stable state to the first stable state.

[0031] Figure 4 Schematic diagram of the magnetization direction of four triangular magnetic soft structures on the magnetic drive provided in an embodiment of the present application, wherein (a) corresponds to the first stable state and (b) corresponds to complete flattening.

[0032] Figure 5 It is a schematic diagram of a method for manufacturing a bistable magnetic actuator provided in an embodiment of the present application.

[0033] Figure 6 It is a schematic diagram of the states of magnetic particles in the magnetic soft material provided in the embodiment of the present application before and after magnetization.

[0034] Figure 7 It is a schematic diagram of the direction of applied magnetic field required for mutual transition between two stable states provided in an embodiment of the present application, wherein (a) corresponds to the transition from the first stable state to the second stable state, and (b) corresponds to the transition from the second stable state to the first stable state.

[0035] Figure 8 It is a gripper composed of a magnetic driver with a bistable characteristic provided in an embodiment of the present application, wherein (a) corresponds to a first stable state and (b) corresponds to a second stable state.

[0036] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0037] 1-magnetic soft layer, 2-bistable composite material layer, 11-first region, 12-second region, 13-third region, 14-fourth region, 21, 22, 23, 24-single-layer board. DETAILED DESCRIPTION

[0038] For ease of understanding, the English abbreviations and related technical terms involved in the embodiments of the present application are explained and described below.

[0039] A laminated cylindrical shell is a cylindrical shell structure composed of multiple layers of different materials or materials with different properties. This structure is usually made of composite materials, and each layer of material has a specific direction and function to improve the strength and stiffness of the overall structure while reducing weight.

[0040] When the side of a cylinder is "cut" and unfolded into a plane, the resulting shape is a cylindrical shell.

[0041] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0042] like Figure 1 As shown, the present application provides a bistable magnetic driver, comprising: a bistable composite material layer 2 and a magnetic soft layer 1 covering the upper surface and / or lower surface of the bistable composite material layer 2; the bistable composite material layer 2 is a laminated cylindrical shell structure; the magnetic soft layer 1 is a rectangular parallelepiped structure, and presents a cylindrical shell shape adaptively with the curing of the bistable composite material layer; the magnetic soft layer 1 includes uniformly laid magnetic particles, and the magnetic particles are magnetized before curing, and the magnetization direction is axial or circumferential to the surface of the bistable composite material layer. θ represents a preset laying angle, and α represents the angle between the fiber direction and the axial direction of the first stable cylindrical shell.

[0043] The bistable composite material layer 2 described in the present application is embedded in the magnetic soft layer 1, providing the magnetic drive with bistable characteristics; the magnetic soft layer 1 completely covers the surface of the bistable composite material layer 2, and is deformed by the magnetic torque in a uniform magnetic field. While ensuring the bistable characteristics of the bistable composite material structure, the present application uses the magnetic soft layer to control it contactlessly, and is suitable for magnetic drives that require large deformation, fast response, and the ability to maintain a deformed state autonomously.

[0044] Preferably, the magnetic soft layer is multi-directionally magnetized so that its deformation trend is consistent with that of the surface of the bistable composite material layer.

[0045] It should be noted that compared with the prior art where a single magnetization can only provide force in a single direction, the present application further designs the magnetization direction of the magnetic soft layer. On the basis of the overall consistent magnetization direction of the magnetic drive, different regions adopt different magnetization directions, which brings deformations in different directions, so that the magnetic torque distribution of the magnetic drive is more consistent with the driving force required for it to produce deformation, thereby reducing the magnetic field required for the magnetic drive to produce deformation, and reducing its driving difficulty and driving energy consumption.

[0046] Preferably, the magnetic soft layer 1 is divided into four regions along a diagonal line, the first region 11 and the third region 13 are identical and arranged opposite to each other, and the second region 12 and the fourth region 14 are identical and arranged opposite to each other.

[0047] Preferably, the magnetization direction of the first region and the third region is along the axial direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell; the magnetization direction of the second region and the fourth region is along the circumferential direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell, and the bistable magnetic drive is in a first stable state.

[0048] Preferably, the magnetization direction of the second region and the fourth region is along the axial direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell; the magnetization direction of the first region and the third region is along the circumferential direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell, and the bistable magnetic drive is in a second stable state.

[0049] Preferably, the thickness of the magnetic soft layer is 0.5 mm-1 mm.

[0050] Preferably, the unidirectional fiber reinforced composite material in the bistable composite material layer is laid in an anti-symmetrical manner.

[0051] Preferably, the bistable magnetic actuator is in the shape of a cylindrical shell in both stable states, and the bending directions in the two stable states are the same.

[0052] Preferably, the bistable magnetic drive is applied to a flexible gripper or a multistable robot.

[0053] Example

[0054] In the bistable magnetic driver of this embodiment, the magnetic soft layer covers the upper and lower surfaces of the bistable composite material layer. According to different magnetization directions, the bottom diagonal line of the rectangular parallelepiped is divided into four triangular magnetic soft structures. The magnetization directions of the upper and lower magnetic soft structures are strictly the same, specifically including: 1) in the first stable state, the upper and lower surfaces connected to the curved edges have a total of 4 magnetic soft structures, and their magnetization directions are along the axial direction of the cylindrical shell surface and outward relative to the center of the bistable composite laminated cylindrical shell; the upper and lower surfaces connected to the straight edges have a total of 4 magnetic soft structures, and their magnetization directions at each location should be along the circumferential direction of the cylindrical shell surface and inward relative to the center of the bistable composite laminated cylindrical shell; 2) in the second stable state, the upper and lower surfaces connected to the curved edges have a total of 4 magnetic soft structures, and their magnetization directions are along the axial direction of the cylindrical shell surface and inward relative to the center of the bistable composite laminated cylindrical shell; the upper and lower surfaces connected to the straight edges have a total of 4 magnetic soft structures, and their magnetization directions at each location should be along the circumferential direction of the cylindrical shell surface and outward relative to the center of the bistable composite laminated cylindrical shell.

[0055] In this embodiment, the magnetic soft layer includes a soft base material and magnetic particles, and the mixing ratio of the two is 1:1. The higher the content of magnetic particles, the lower the driving difficulty. The soft base material is organic silica gel, and the magnetic particles are permanent magnetic particles that have been initially magnetized before curing, specifically NdFeB powder, with a particle size of 5-10μm. The greater the thickness of the magnetic soft layer, the lower the mass fraction of magnetic particles is to achieve the same driving effect.

[0056] The magnetic soft layer may also only cover the upper surface or the lower surface of the bistable composite material layer.

[0057] The four regions divided by the magnetic soft layer along the diagonal line may also be in the shape of triangles.

[0058] The bistable composite material layer is a thin rectangular multilayer laid fiber reinforced composite material structure cured into a cylindrical shell shape; the single-layer plate material is a unidirectional carbon fiber / epoxy resin fiber composite material, or a composite material of glass fiber and other curing agents.

[0059] like Figure 1 As shown, the bistable composite laminated cylindrical shell is laid in an anti-symmetric manner: the laying angle is defined as the angle between the fiber direction of the unidirectional carbon fiber in the composite single-layer plate and the longitudinal direction during laying, i.e., the y-axis. The anti-symmetric laying is composed of at least 4 layers of single-layer plates (21, 22, 23 and 24), each of which has a thickness of 0.125 mm, and relative to the geometric mid-plane of the laminate, the single-layer plates correspond to each other in pairs, the laying angles are the same in size and opposite in direction, and the material properties are the same.

[0060] The bistable composite laminated cylindrical shell needs to be heated and cured in a cylindrical mold after laying. After curing, it exhibits bistable characteristics due to the mechanical properties of carbon fiber with a special laying method. Its two stable states are as follows: Figure 2 The two stable states, after curing, are as shown in Figure 2 The cylindrical shell shown in (a) is the first stable state. When the load reaches the transition condition, the straight edge of the first stable state becomes a curved edge, and the curved edge becomes a straight edge, and the same is maintained. Figure 2 The new cylindrical shell shape shown in (b) remains unchanged, which is the second stable state. The two stable states both present a cylindrical shell shape and have the same bending direction.

[0061] When the bistable composite laminated cylindrical shell is converted from the first stable state to the second stable state, the torque direction required at each edge is as follows: Figure 3 As shown in (a): the two straight sides require an outward torque relative to the cylindrical shell, and the two curved sides require an inward torque relative to the cylindrical shell.

[0062] When the bistable composite laminated cylindrical shell is converted from the second stable state to the first stable state, the torque direction required at each edge is as follows: Figure 3 As shown in (b): the two straight sides require an outward torque relative to the cylindrical shell, and the two curved sides require an inward torque relative to the cylindrical shell.

[0063] When the bistable composite laminated cylindrical shell is in the first stable state or completely flattened, the magnetization directions of the magnetic soft structure are as follows: Figure 4 As shown in (a) and (b), the y-axis direction is the axial direction of the first stable cylindrical shell, and the x-axis is perpendicular to the y-axis. When the bistable composite laminated cylindrical shell is in the first stable state, the magnetization direction of the 4 magnetic soft structures on the upper and lower surfaces connected to the curved edge is along the y-axis direction, and is outward relative to the center of the bistable composite laminated cylindrical shell; the magnetization direction of the 4 magnetic soft structures on the upper and lower surfaces connected to the straight edge should be along the tangent direction of the cylindrical shell surface, and inward relative to the center of the bistable composite laminated cylindrical shell.

[0064] The magnetic soft structure is magnetized in the above direction, when the magnetic driver is in the first steady state, a vertical magnetic field is applied, and the magnetic torque acts on the whole structure to generate torque and Figure 3 (a) is consistent, that is, the straight-side torque is outward relative to the cylindrical shell, and the curved-side torque is inward relative to the cylindrical shell, which can drive the embedded bistable composite laminated cylindrical shell to transform from the first stable state to the second stable state. In this embodiment, the uniform magnetic field is 250mT.

[0065] The magnetic soft structure is in the above magnetization direction, when the magnetic driver is in the second stable state, a vertical downward magnetic field is applied, and the magnetic torque acts on the overall structure to generate torque and Figure 3 (b) is consistent with the figure, that is, the straight-side torque is outward relative to the cylindrical shell, and the curved-side torque is inward relative to the cylindrical shell, which can drive the embedded bistable composite laminated cylindrical shell to transform from the second stable state to the first stable state.

[0066] When the magnetic drive provided in the present application is in use, under the action of the applied magnetic field, the magnetized particles in the magnetic soft structure are subjected to the magnetic torque, driving the magnetic soft structure to deform. When the deformation is large enough, the embedded bistable composite laminated cylindrical shell spontaneously transforms to another stable state; after the deformation is completed, even if the magnetic field is removed, the magnetic drive can autonomously maintain the deformed state.

[0067] The magnetic driver provided in the present application, by introducing a bistable composite laminated cylindrical shell, imparts bistable characteristics to the magnetic soft structure, thereby ensuring sufficient deformation while improving the deformation response speed, and enabling it to spontaneously maintain the stability of the deformed state without the need for continuous input of external loads, thereby reducing the energy consumption required for driving and maintaining the deformation; in addition, after optimizing the magnetization direction of the magnetic soft structure, the magnetic torque exerted on each part of the magnetic driver under the action of an external magnetic field is more in line with the deformation law of the bistable composite laminated cylindrical shell, and the driving magnetic field can also be reduced, thereby further reducing the driving difficulty and driving energy consumption.

[0068] like Figure 5 As shown, the present application provides a method for manufacturing a bistable magnetic actuator, comprising:

[0069] S1. Mixing the uncured soft base material liquid with the magnetic particles and stirring them evenly to obtain a magnetic mixture fluid;

[0070] S2. The magnetic mixture fluid is injected into a rectangular parallelepiped mold for injection molding and curing. After standing and curing, an unmagnetized rectangular parallelepiped magnetic soft structure is obtained. The static curing time is 1h-2h;

[0071] S3. placing the unmagnetized rectangular magnetic soft structure in a uniform pulse magnetic field for magnetization to obtain a rectangular magnetic soft structure with a specific magnetization direction;

[0072] S4. The uncured composite single-layer board is cut according to a preset laying angle, and then laid according to a preset laying method to obtain an uncured anti-symmetrically laid composite laminate; the preset laying angle is 40 ° -60 °;

[0073] S5. Cut the rectangular magnetic soft structure with a specific magnetization direction obtained in S3 according to a preset shape and magnetization direction, and use the same uncured soft base material liquid as in S1 as an adhesive to bond all the magnetic soft structures with a preset shape and magnetization direction to the upper surface and / or lower surface of the uncured anti-symmetrically laid composite material laminate obtained in S4 in a preset manner to obtain an uncured magnetic actuator;

[0074] S6. Placing the uncured magnetic actuator in a cylindrical mold for heating and curing to obtain a magnetic actuator with bistable characteristics.

[0075] As a preferred embodiment, the magnetization in step S3 is performed using a short-time pulse magnetic field of 2T for a few seconds. After the magnetization is completed, the magnetization directions of the magnetic particles are the same, which is manifested as a fixed magnetization direction of the rectangular magnetic soft structure. The strong magnetic field of 2T can ensure the uniformity of the magnetization direction of the magnetized particles.

[0076] As a preferred implementation, the short-duration pulse magnetic field generating device includes a power supply, a power supply control system and an electromagnetic coil.

[0077] As a preferred implementation, in step S1, 3D printing can be used when preparing the mold; and when designing the mold size, the size of the magnetic soft structure must be fully considered and sufficient margin must be left.

[0078] As a preferred embodiment, a stirring and degassing machine can be used during stirring and mixing. During stirring, the rotation speed is 2000 r / min and the stirring time is 2 min; after stirring, the mixture is degassed, and during degashing, the rotation speed is 2200 r / min and the degassing time is 1.5 min.

[0079] As a preferred embodiment, in step S2, when injecting the magnetic mixture fluid into the mold, it should be noted that the fluid viscosity is relatively high, and the injection speed is too fast to avoid the formation of bubble cavities; it should also be noted that the fluid solidifies quickly after mixing, and the injection speed is too slow to avoid the rapid increase of the fluid viscosity, making the injection process difficult and generating additional bubble cavities.

[0080] As a preferred embodiment, after the magnetic mixture fluid is injected into the mold, a scraper is used to remove excess fluid to ensure a smooth injection molding surface.

[0081] As a preferred embodiment, after being completely filled, the magnetic mixture fluid should be left to stand at room temperature for 4 hours or heated at 60° C. for 45 minutes to be completely solidified.

[0082] As a preferred embodiment, when magnetizing, the process is as follows: put the mold and the fully solidified magnetic soft structure that has not been removed into the pulse magnetic field generating device according to the pre-designed magnetization direction; it should be noted that the mold and the fully solidified magnetic soft structure that has not been removed should be completely fixed before magnetizing to prevent displacement and deformation during magnetizing; magnetize the whole by applying a 2T pulse magnetic field. It should be noted that the solenoid coil should be long enough to ensure that the magnetic field of each part of the magnetic soft structure remains uniform during magnetization.

[0083] Before and after magnetization, the state of magnetic particles in the magnetic soft structure is as follows: Figure 6 After magnetization, the magnetization direction of the magnetic particles is consistent. Under the action of an external driving magnetic field, magnetic torques in the same direction can be generated, thereby causing the magnetic soft structure to produce predictable elastic deformation.

[0084] As a preferred implementation, in step S4, the composite single-layer plate should be a fiber-reinforced composite material with a single fiber direction such as unidirectional carbon fiber / epoxy resin.

[0085] As a preferred embodiment, the magnetic driver described in the present application is in the shape of a cylindrical shell, so when cutting the single-layer composite material plate, it should be cut into a rectangle according to the laying method and laying angle.

[0086] As a preferred embodiment, in step S5, when selecting an adhesive, the same uncured soft base material liquid as in step S1 should be selected, and the curing method and environmental conditions should be the same as in step S2, so as to ensure sufficient bonding effect while the mechanical properties of the soft structure are similar. In addition, when using the adhesive for bonding, the surface of the magnetic soft structure should be properly squeezed to prevent air from being trapped and generating bubbles that affect the bonding effect.

[0087] As a preferred embodiment, in step S6, before the uncured magnetic driver is heated and cured, it should be pre-bent on the surface of the cylindrical mold and made to fit completely with the cylindrical mold. At the same time, it should maintain this shape and be completely fixed to prevent it from detaching and deforming during the heating process. During heating and curing, the heating temperature is 120℃-150℃, and the heating time is 30min-45min. During the heating process, it should be ensured that all parts of the magnetic driver are heated evenly to prevent deformation due to excessive local temperature.

[0088] like Figure 7 As shown, the present application also provides a driving method of the above-mentioned bistable magnetic actuator, wherein the curled side is flattened and fixed in a fixture. Figure 7 As shown in (a), when the magnetic drive is transformed from the first stable state to the second stable state, a uniform vertical magnetic field needs to be applied to make the curved side flatten inward and the straight side bend outward by using the magnetic torque. After reaching a certain degree of deformation, the magnetic drive will automatically jump and quickly transform from the first stable state to the second stable state. After the driving magnetic field is removed, the magnetic drive will autonomously maintain the shape of the second stable state. Figure 7 As shown in (b), when the magnetic drive is transformed from the second stable state to the first stable state, a uniform magnetic field needs to be applied vertically downward. The magnetic torque on each side is opposite to that in the process from the first stable state to the second stable state, but similarly, the straight side turns outward and bends, and the curved side turns inward and flattens. After reaching a certain degree of deformation, the magnetic drive will automatically jump and quickly transform from the second stable state to the first stable state. After the driving magnetic field is removed, the magnetic drive will autonomously maintain the shape of the first stable state. This method can reduce the driving load of the magnetic drive, that is, the driving magnetic field, to a large extent while providing effective fixation.

[0089] Based on the above embodiments, the present application provides a flexible gripper consisting of a fixed fixture and two bistable magnetic actuators, such as Figure 8As shown. The magnetization directions of the two magnetic actuators should be opposite to each other so that magnetic moments in opposite directions are generated under the action of magnetic fields in the same direction, so that they are curled or unfolded at the same time. Both magnetic actuators are flattened on one side and fixed in a fixture.

[0090] When the two magnetic drives are in the first stable state, the gripper is in an open state, such as Figure 8 As shown in (a); when the two magnetic drives are in the second stable state, the gripper is in a closed state, as shown in Figure 8 As shown in (b), the object to be grasped can be grasped, and based on the elasticity and flexible structure of the magnetic drive, it can grasp objects of different shapes and ensure a certain degree of adaptability without causing damage to the grasped object.

[0091] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0092] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0093] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the relative position relationship after connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0094] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, verticality, etc. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense, and allow a small amount of deviation, approximation to symmetry, approximation to equality, approximation to parallelism, approximation to verticality, etc. are all possible. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0095] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A bistable magnetic actuator, characterized in that: include: A bistable composite material layer and a magnetic soft layer covering the upper surface and / or the lower surface of the bistable composite material layer; The bistable composite material layer is a laminated cylindrical shell structure; The magnetic soft layer is a rectangular parallelepiped structure, and adaptively presents a cylindrical shell shape as the bistable composite material layer solidifies; The magnetic soft layer comprises uniformly laid magnetic particles, which are magnetized before solidification, and the magnetization direction is axial or circumferential on the surface of the bistable composite material layer.

2. The bistable magnetic actuator according to claim 1, wherein: The magnetic soft layer is multi-directionally magnetized so that its deformation trend is consistent with that of the surface of the bistable composite material layer.

3. The bistable magnetic actuator according to claim 2, wherein: The magnetic soft layer is divided into four regions along a diagonal line, the first region and the third region are identical and arranged oppositely, and the second region and the fourth region are identical and arranged oppositely.

4. The bistable magnetic actuator according to claim 3, characterized in that The magnetization directions of the first and third regions are along the axial direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell; the magnetization directions of the second and fourth regions are along the circumferential direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell, and the bistable magnetic drive is in a first stable state.

5. The bistable magnetic actuator according to claim 3, characterized in that: The magnetization directions of the second region and the fourth region are along the axial direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell; the magnetization directions of the first region and the third region are along the circumferential direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell, and the bistable magnetic drive is in a second stable state.

6. The bistable magnetic actuator according to claim 1, wherein: The thickness of the magnetic soft layer is 0.5mm-1mm.

7. The bistable magnetic actuator according to claim 1, wherein: The unidirectional fiber-reinforced composite material in the bistable composite material layer is laid in an anti-symmetrical manner.

8. The bistable magnetic actuator according to claim 1, wherein: The bistable magnetic driver is in the shape of a cylindrical shell in both stable states, and the bending directions in the two stable states are the same.

9. The bistable magnetic actuator according to any one of claims 1 to 8, characterized in that: The bistable magnetic actuator is applied to a flexible gripper or a multistable robot.

10. A method for manufacturing a bistable magnetic actuator, characterized in that: include: S1. Mixing the uncured soft base material liquid with the magnetic particles and stirring them evenly to obtain a magnetic mixture fluid; S2. injecting the magnetic mixture fluid into a rectangular parallelepiped mold, performing injection molding and curing, and obtaining an unmagnetized rectangular parallelepiped magnetic soft structure after standing and curing; S3. placing the unmagnetized rectangular magnetic soft structure in a uniform pulse magnetic field for magnetization to obtain a rectangular magnetic soft structure with a specific magnetization direction; S4. The uncured composite single-layer plate is cut according to a preset laying angle, and then laid according to a preset laying method to obtain an uncured anti-symmetrically laid composite laminate; S5. Cut the rectangular magnetic soft structure with a specific magnetization direction obtained in S3 according to a preset shape and magnetization direction, and use the same uncured soft base material liquid as in S1 as an adhesive to bond all the magnetic soft structures with a preset shape and magnetization direction to the upper surface and / or lower surface of the uncured anti-symmetrically laid composite material laminate obtained in S4 in a preset manner to obtain an uncured magnetic actuator; S6. Placing the uncured magnetic actuator in a cylindrical mold for heating and curing to obtain a magnetic actuator with bistable characteristics.

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